It's a 6 foot radius net to start with but once you get good you really need at least a 10 foot radius net to tear em' up. Here in Ms we use a "brill net " and it has a chain sewn into the bottom edge and no mono leaders inside for bunching it up like a cast net does when you pull it. We chum the shrimp to the area with pelletized rabbit food off a pier or boat launch at night and if you can put a light shining onto the water It's even better.
brill nets have strings that run from the leadline to the handline,that closes the net when pulled.spanish castnets have a bag at the bottom of the net.